Gait assistive device and walking robot having the same

ABSTRACT

A gait assistive device that may be used to improve a gait disability by replacing or compensating movement of joints of an ankle and a foot that occur during a gait or that may be used for a bottom structure of a gait robot is disclosed. 
     The present invention provides a gait assistive device including: a foot supporting part; a rear connecting part coupled to a heel portion of the foot supporting part; and a rearfoot plate coupled to the rear connecting part, wherein the rear connecting part may include a joint, and a shaft of the joint is installed on a line or rear line of a load line at heel strike during a gait cycle based on a direction of a gait.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional Application of U.S. patent applicationSer. No. 16/843,995 filed on Apr. 9, 2020, which is a Continuationapplication of PCT/KR2018/011993 filed on Oct. 11, 2018, which claimspriority to and the benefit of Korean Patent Application No.10-2017-0129752 filed in the Korean Intellectual Property Office on Oct.11, 2017, and Korean Patent Application No. 10-2018-0121293 filed in theKorean Intellectual Property Office on Oct. 11, 2018, the entirecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION (a) Field of the Invention

The present invention relates to a gait assistive device and walkingrobot having the same, and more particularly, to a gait assistive deviceand walking robot having the same that may be used to improve a gaitdisability by replacing or compensating a movement of joints of an ankleand a foot that occur during a gait or that may be used for a bottomstructure of a gait robot.

(b) Description of the Related Art

A gait is a movement that moves a human body in a desired directionwhile maintaining a stable weight load posture with respect to theground, and thus force applied to the ground by a human body and groundreaction force GRF, which is a force of reaction to the force applied tothe ground by the human body, are generated.

A normal gait is a very efficient movement that uses both activemovement by muscle contraction and passive movement of joints of anankle and a foot by the GRF.

When joint movement is limited by a splint or a cast due to a fractureof a lower limb, a ligament injury, or the like, or when joint movementshould be limited by Charcot foot, ankle and foot arthropathies, or thelike, since sufficient movements of joints of ankle and foot do notoccur during the gait, a normal gait pattern is not achieved. Sinceordinary shoes, cast shoes, rocker bottom shoes, and a conventionalassistive device that are worn in this case do not take into accountground reaction force occurring during the gait, they do not achieve anefficient gait, and rather they may also adversely affect the gait dueto a modified ground reaction force.

Even in gait disorders caused by central nervous system diseases such asa stroke, a brain injury, a brain tumor, and a cerebral palsy, a normalgait is impossible because muscle weakness and muscle stiffness do notallow normal movements of joints of the ankle and foot. An ankle footorthosis (AFO), which is typically used in the related art, restrictsjoint movement of the ankle and the foot, and thus an efficient gaitusing the ground reaction force is absolutely impossible.

In addition, since gait robots that have been developed to date do notuse the ground reaction force as efficiently as a human gait, a largenumber of driving devices outputting great force are required, and thuscontrol and battery devices are also getting bigger, and further, weightand volume, as well as manufacturing costs, are increased.

SUMMARY OF THE INVENTION

Therefore, the present invention has been proposed to solve the aboveproblems, and an object of the present invention is to provide a gaitassistive device for achieving an efficient gait by using groundreaction force GRF.

Another object of the present invention is to provide a gait assistivedevice that compensates for movement of joints of an ankle and a footwhen the movement of the joints of the ankle and the foot is limited ormust be limited.

Another object of the present invention is to provide a gait assistivedevice that can help a patient with a gait disorder caused by nervoussystem damage achieve a stable gait by utilizing ground reaction forceGRF.

In addition, another object of the present invention is to provide awalking robot that may be used in a bottom structure of a gait robot toreduce weights of a driving device, a control device, and a batterydevice.

The present invention provides a gait assistive device including: a footsupporting part; a rear connecting part coupled to a heel portion of thefoot supporting part; and a rearfoot plate coupled to the rearconnecting part, wherein the rear connecting part may include a joint,and the joint is disposed on or behind a load line at a first half ofstance phase during a gait cycle with respect to the direction ofwalking.

An angle maintaining portion that adjusts a load applied along the loadline at the first half of stance phase or maintains the rearfoot plateat a constant angle after heel off or during a swing phase of the gaitcycle may be provided between the foot supporting part and the rearfootplate.

The foot supporting part may be coupled to a rear moving member movingin a longitudinal direction of the foot supporting part, a position ofthe rear moving member may be adjusted by a rear adjusting member, andthe rear connecting part may be coupled to the rear moving member.

The foot supporting part may be coupled to a front supporting part at afront side of the foot.

A front connecting part may be coupled to a front side of the footsupporting part, and a forefoot plate may be coupled to the frontconnecting part.

The foot supporting part may be coupled to a front moving member movingin the shaft direction, a position of the front moving member may beadjusted by a front adjusting member, and the front connecting part maybe coupled to the front moving member.

The forefoot plate and the forefoot plate may be coupled to a plateconnecting part that transmits interlocking movement therebetween.

A coronal adjusting part that transversely adjusts the forefoot platemay be installed between the forefoot plate and the foot supportingpart.

A coronal adjusting part that transversely adjusts the rearfoot platemay be installed between the rearfoot plate and the foot supportingpart.

A load adjusting part that adjusts the load applied along the load lineat a first half of stance phase may be installed between the footsupporting part and the rearfoot plate.

The joint may have a structure that allows the rearfoot plate to move ina coronal or sagittal plane, or simultaneously allows the rearfoot plateto move in the coronal and sagittal planes.

The coronal adjusting part may be made of at least one of an elasticmember, a torsion spring, and a chamber provided with a spaceaccommodating a fluid, and the chamber may be connected to a flowadjusting valve that adjusts an amount of the fluid of the chamber.

Further, another embodiment of the present invention provides a gaitassistive device including: a foot supporting part; a rear connectingpart coupled to a heel portion of the foot supporting part; a rearfootplate coupled to the rear connecting part; a front connecting partcoupled to a front side of the foot supporting part; and a forefootplate coupled to the front connecting part, wherein the front connectingpart may include a joint, and the joint may be installed between a loadline formed at a heel off and a load line formed at a toe off, during agait cycle based on a gait proceeding direction.

Another embodiment of the present invention provides a walking robot,including: a foot supporting part; a rear connecting part coupled to aheel portion of the foot supporting part; and a rearfoot plate coupledto the rear connecting part, wherein the rear connecting part mayinclude a joint, and the joint may be installed on or behind a load lineat a first half of stance phase during a gait cycle with respect to thedirection of walking.

The present invention has an effect of naturally achieving a gait of apatient without causing passive movements of joints of ankle and foot.

The present invention has a convenient effect of being used in real lifeby securing weight-lighting and wearability and functionality through aform of boots that may be worn in clothes (for example, pants) for apatient with a central nervous system disease in which the strength ofhip muscles is maintained to some extent.

The present invention has an effect of increasing patient application bybeing configured of a structure that may be generally used.

The present invention has an effect of increasing stability of a gait ofa walking robot by being applied to a bottom structure of the walkingrobot.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a stance phase divided into five stages forexplaining a general human gait cycle.

FIG. 2 illustrates articular surfaces positioned along a longitudinalaxis of a lower limb skeleton of a human.

FIG. 3 illustrates a schematic view for explaining a load line of ahuman body and ground reaction force GRF at a moment of heel strikeduring a general gait cycle.

FIG. 4 illustrates a gait assistive device in which a load line andground reaction force GRF are shown in a heel strike state during a gaitcycle for explaining a first embodiment of the present invention.

FIG. 5 illustrates a schematic view for explaining a load line andground reaction force GRF in a heel strike state of a general gaitcycle.

FIG. 6 illustrates a schematic view for explaining a second embodimentof the present invention and a heel strike during a gait cycle.

FIG. 7 illustrates a schematic view for explaining another example ofthe second embodiment of the present invention.

FIG. 8 illustrates a schematic view for explaining still another exampleof the second embodiment of the present invention.

FIG. 9 illustrates a schematic view for explaining a midstance during agait cycle of a second embodiment of the present invention.

FIG. 10 illustrates a schematic view for explaining a heel off during agait cycle of a second embodiment of the present invention.

FIG. 11 illustrates a gait assistive device for explaining a thirdembodiment of the present invention.

FIG. 12 illustrates a gait assistive device for explaining a fourthembodiment of the present invention.

FIG. 13 illustrates a gait assistive device for explaining a fifthembodiment of the present invention.

FIG. 14 illustrates a schematic view of an angle maintaining part thatmay set an angle of a rearfoot plate of a gait assistive device forexplaining a sixth embodiment of the present invention.

FIG. 15 illustrates a rear connecting part of a gait assistance devicefor explaining a seventh embodiment of the present invention.

FIG. 16 illustrates a side view of a state in which the rear connectingpart of FIG. 15 is assembled.

FIG. 17 illustrates a rear side of a state in which the rear connectingpart of FIG. 15 is assembled.

FIG. 18 illustrates a rear connecting part of a gait assistance devicefor explaining an eighth embodiment of the present invention.

FIG. 19 illustrates an exploded perspective view of a main part of therear connecting part of the gait assistance device shown in FIG. 18 .

FIG. 20 illustrates a rear portion of a foot in a state in which a loadline and ground reaction force GRF pass through an ankle joint and asubtalar joint in the seventh and eighth embodiments of the presentinvention.

FIG. 21 illustrates a schematic view for explaining a conventionalexample corresponding to FIG. 20 .

FIG. 22 illustrates a bottom view of a gait assistive device forexplaining a ninth embodiment of the present invention.

FIG. 23 illustrates a schematic view of a rear connecting part of a gaitassistance device for explaining a tenth embodiment of the presentinvention.

FIG. 24 illustrates a schematic view of a gait assistance device forexplaining an eleventh embodiment of the present invention.

FIG. 25 illustrates a schematic view of a gait assistance device forexplaining a twelfth embodiment of the present invention.

FIG. 26 illustrates a schematic view of a gait assistance device forexplaining a thirteenth embodiment of the present invention.

FIG. 27 illustrates an exploded perspective view of a main part of FIG.26 .

FIG. 28 illustrates a schematic view of a foot supporting part of thethirteenth embodiment of the present invention.

FIG. 29 illustrates a schematic view for explaining a setting process ofa rear connecting part coupled to the foot supporting part according tothe thirteenth embodiment of the present invention.

FIG. 30 illustrates a schematic view of a plate connecting part of thethirteenth embodiment of the present invention.

FIG. 31 illustrates an operation example of a coronal adjusting part ofthe thirteenth embodiment of the present invention.

FIG. 32 illustrates a schematic view for explaining a relative positionof ground reaction force GRF with respect to a joint axis of a rearconnecting part at a heel strike during a gait cycle of the thirteenthembodiment of the present invention.

FIG. 33 illustrates a schematic view for explaining a position at whicha load line and ground reaction force GRF are moved in a midstanceprocess during a gait cycle of the thirteenth embodiment of the presentinvention.

FIG. 34 illustrates a schematic view for explaining a relative positionof ground reaction force GRF with respect to a joint axis of a frontconnecting part at a heel off during a gait cycle of the thirteenthembodiment of the present invention.

FIG. 35 illustrates a schematic view for explaining a relative positionof ground reaction force GRF with respect to a joint axis of a frontconnecting part at a toe off during a gait cycle of the thirteenthembodiment of the present invention.

FIG. 36 illustrates an operating state of a coronal adjusting part forexplaining the thirteenth embodiment of the present invention.

FIG. 37 illustrates a schematic view for explaining a fourteenthembodiment of the present invention.

FIG. 38 illustrates a cross-sectional view taken along line A-A of FIG.37 .

FIG. 39 illustrates a schematic view for explaining a fifteenthembodiment of the present invention.

FIG. 40 illustrates a cross-sectional view taken along line B-B of FIG.39 .

FIG. 41 illustrates a cross-sectional view for explaining a sixteenthembodiment of the present invention.

FIG. 42 illustrates a schematic view for explaining a seventeenthembodiment of the present invention.

FIG. 43 illustrates a schematic view for explaining an eighteenthembodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention will be described more fully hereinafter withreference to the accompanying drawings, in which embodiments of theinvention are shown. As those skilled in the art would realize, thedescribed embodiments may be modified in various different ways, allwithout departing from the spirit or scope of the present invention. Thedrawings and description are to be regarded as illustrative in natureand not restrictive, and like reference numerals designate like elementsthroughout the specification.

In the present specification, unless explicitly described to thecontrary, the word “comprise” and variations such as “comprises” or“comprising” will be understood to imply the inclusion of statedelements but not the exclusion of any other elements.

Hereinafter, a body center direction is referred to as an “inner side”,a direction opposite to the “inner side” is referred to as an “outerside”, a toe direction is referred to as a “forward side”, and a heeldirection is referred to as a “rear side”. In addition, a “lengthdirection” means a direction connecting a toe from a heel, and a “widthdirection” means a direction perpendicular to the length direction as awidth of a foot.

An open kinetic chain (OKC) and a closed kinetic chain (CKC) as termsused in the detailed description of the present invention are defined asfollows.

The closed kinetic chains (CKC) is a state in which a force is appliedto a fixed object such as the ground and a wall by the movement of ahuman body, such as in activities such as gait or push-up. In this case,when the human body applies force to the fixed object, reaction forceoccurs simultaneously from the fixed object, and thus the reaction forcefrom the fixed object also affects the movement of the human body.

On the contrary, the open kinetic chain (OKC) is a state in which thehuman body applies force on the unfixed object, such as in activitiessuch as bench press and leg curl, and the object is freely moved by themovement of the human body. Therefore, reaction force that affects themovement of the human body does not occur.

In addition, in the description of the embodiment of the presentinvention, body load force (BLF) is force applied to the ground by thehuman body through a foot contacting the ground in the closed kineticchain movement such as gait, and a load line (LL) is a line indicating adirection in which body load force is applied. Ground reaction force GRFis a reaction force to the body load force, which is opposite to a forceof the same magnitude as the body load force. A direction of the loadline depends on a position of a point in contact with the ground, andalso depends on a contact shape, for example, point contact or planecontact.

In the description of the present invention, an external moment isdefined as a rotational force generated in each joint by the groundreaction force GRF, and an internal moment is defined as a rotationalforce generated in each joint by muscle contraction.

A human gait cycle is as follows.

In FIG. 1 , (a) to (e) are schematic views for explaining a human gaitcycle.

The human gait cycle is divided into a stance phase and a swing phasebased on one foot (hatched portions in the drawing).

The stance phase is a state in which the foot contacts the ground whilewalking. The stance phase includes heel strike (FIG. 1 (a)), loadingresponse (FIG. 1 (b)), midstance (FIG. 1 (c)), heel off (FIG. 1 (d)),and toe off (FIG. 1 (e)).

The heel strike means a moment when the outside of the heel contacts theground during the stance phase. At this time, plantar flexion of anankle joint occurs by the ground reaction force GRF and pronation andeversion are generated in the subtalar joint, by the ground reactionforce GRF, so that an impact against the ground may be absorbed (asshown in FIG. 1 (a))

The loading reaction is a process in which, while the entire solecontacts the ground after the heel strike, constant pronation occurs toabsorb the impact applied to the foot and to disperse the body weight toadapt the foot to uneven ground (as shown in FIG. 1 (b)).

The midstance is a stage where the body weight is maximally loaded onthe foot (as shown in FIG. 1 (c)).

The heel off is a stage where the heel of the foot is lifted up (asshown in FIG. 1 (d)).

The toe off is a stage where the toe of the foot is lifted up (as shownin FIG. 1 (e)).

On the other hand, the swing phase means a state in which the foot isaway from the ground.

The gait is realized by repeatedly performing the stance phase and theswing phase.

FIG. 2 illustrates articular surfaces positioned along a longitudinalaxis of a lower limb skeleton of a human. In the standing posture, theload line LL passes through the knee joint KJ, ankle joint A, andsubtalar joint B along the longitudinal axis of the lower limb skeleton.When a weight is loaded at a fixed object such as the ground, the loadline LL passes through a point of contact with the ground along thelongitudinal axis of the leg skeleton, and the ground reaction force GRFof the same magnitude is generated in an opposite direction thereto dueto reaction thereto.

That is, the load line LL is a line indicating a direction of the bodyload force applied to the ground by the human body, and is directed to apoint CP contacting the ground along the longitudinal axis of the lowerlimb at a moment of heel strike.

FIG. 3 illustrates a schematic view for explaining a load line of ahuman body and ground reaction force GRF at a moment of heel strikeduring a general gait cycle. The load line LL is directed to a portionat which the heel of the foot contacts the ground G along an axis of aleg, and the ground reaction force GRF occurs in an opposite directionthereof.

FIG. 4 is a schematic view for explaining a first embodiment of thepresent invention, and illustrates a gait assistance device. The gaitassistive device of the first embodiment of the present inventionincludes a foot fixing part 1, a foot supporting part 3, a rearconnecting part 5, and a rearfoot plate.

The foot fixing part 1 may be worn by a patient like ordinary shoes orcast shoes, and a forefoot supporting part 1 a having a predeterminedheight may be coupled to a bottom of a front side thereof.

The forefoot supporting part 1 a may be formed of an elastic body havinga predetermined elastic force or cushion, and may extend from a toe ofthe foot fixing part 1 to a middle portion of a sole of the foot. Theforefoot supporting part 1 a may be integrally molded with the footfixing part 1 when applied to cast shoes. The forefoot supporting part 1a may be formed to have a shoe sole structure.

The foot supporting part 3 may be formed to have a shape of a plate. Thefoot supporting part 3 may be integrally fixed to a bottom of the footfixing part 1. When the foot supporting part 3 is separated from thefoot fixing part 1, the foot supporting part 3 can be easily combinedwith existing shoes or cast shoes by using a coupling member such as aVelcro fastener.

In the description of the embodiment of the present invention, forconvenience, the foot fixing part 1 and the foot supporting part 3 areseparately described, but the foot fixing part 1 itself may beintegrally formed to serve as the foot supporting part 3. Therefore, inthe description of the embodiment of the present invention, the footsupporting part 3 may include the foot fixing part 1. That is, the rearconnecting part 5 may be coupled to the foot supporting part 3, or maybe directly coupled to the foot fixing portion 1.

Meanwhile, when the foot supporting part 3 is made long in a sole lengthdirection, the forefoot supporting part 1 a may be coupled to a frontside of the foot supporting part 3.

Hereinafter, in the embodiment of the present invention, for convenienceof description, an example in which the rear connecting part 5 iscoupled to the foot supporting part 3 will be described.

The rear connecting part 5 connects the foot supporting part 3 and therearfoot plate 7 at a heel portion of the foot fixing portion 1. Therear connecting part 5 includes a joint structure.

As an example of the joint structure, the rear connecting part 5includes a first member 5 a fixed to the foot supporting part 3, asecond member 5 b coupled to the rearfoot plate 7, and a hinge member Cfor hinge-coupling the first member 5 a and the second member 5 b.

The hinge member C may connect the first member 5 a and the secondmember 5 b so that a width direction of the foot forms a central axis.In the embodiment of the present invention, a rotating axis of the hingemember C means a rotating axis of the joint or a axis of the joint.Therefore, in the rearfoot plate 7, an inclination (also referred to asa pitch, and which means an inclination in the sagittal plane) of thelongitudinal direction of the foot may be adjusted. That is, therearfoot plate 7 may have a pitch of a horizontal or arbitrary anglewhen viewed from the side of the foot with respect to the horizontalground G.

The rearfoot plate 7 is coupled to the second member 5 b of the rearconnecting part 5. The rearfoot plate 7 is preferably made of a flatplate so as to be in plane contact with the ground surface G in the heelstrike step during the gait cycle. The rearfoot plate 7 may be made ofan elastic body having a sufficient size to cover the heel portion andhaving an elastic force. As such, the rearfoot plate 7 may be made ofthe elastic body to alleviate an impact applied to the foot of a patientin the heel strike step.

Meanwhile, it is preferable that the rotating axis of the hinge member Cof the rear connecting part 5 is disposed on or behind the load line LLwhen viewed from a side based on a gait proceeding direction at the heelstrike during the gait cycle. When the rotating axis of the hinge memberis positioned behind the load line LL, a rotating moment caused by theground reaction force GRF causes the first member 5 a fixed to the footsupporting part 3 to rotate in a clockwise direction. In addition, sincethe gait is a movement in which the human body moves forward, inertia inwhich the lower leg rotates clockwise at the heel strike occurs, andthus, even if the rotating axis of the hinge member is positioned on theline of the load line LL, the first member 5 a fixed to the footsupporting part 3 rotates clockwise. Therefore, the patient can walkwith stability without falling.

FIG. 5 illustrates a heel strike time point during a gait cycle in astate of wearing general shoes. In the gait in the state of wearing thegeneral shoes, a rear end portion of the shoe point-contacts the groundG at the heel strike. In this case, when the rear end portion of theshoe point-contacts the ground, since the open kinetic chain (OKC) stateis changed to the closed kinetic chain (CKC) state, the ground reactionforce occurs. In the closed kinetic chain (CKC) state, theaction-reaction force occurs at the contact point, so that the load lineLL is directed to a point at which the ground and the human body are inpoint contact, and the ground reaction force GRF occurs in the oppositedirection thereto. In this case, since the rotating axis of the anklejoint A and the subtalar joint is positioned in front of the load lineLL, the rotating moment caused by the ground reaction force GRF allowsthe foot to be flexed to the ground such that the sole of the foottouches the ground. A rotating moment or torque at this time isproportional to a vertical distance r from an axis of the joint A to aline on which the ground reaction force GRF acts.

Since the ground reaction force (GRF) passes through a front side of theknee joint at a moment of heel strike, a knee extension moment thatcauses the knee to straighten occurs, while in the loading responseimmediately after the heel strike, as the leg rotates forward (the legrotates forward with respect to the foot in contact with the ground) bythe action of the body's forward movement inertia and the contraction ofthe pretibial muscles, the direction of the ground reaction force (GRF)changes rapidly to the rear side of the knee joint. Therefore, in theloading response, a knee flexion moment that causes the knee to be bentdue to ground reaction force (GRF) occurs, which is offset by aninternal moment generated by contraction of the quadriceps muscle toenable a stable gait without bending of the knee.

When the splint, the cast, or the ankle foot orthosis is worn, and whenthere is ankle stiffness due to arthritis or nerve damage, movement inthe ankle and subtalar joints are restricted, so that the impact causedfrom the ground is neither absorbed nor distributed. In addition, therotating moment by the ground reaction force (GRF) in the heel strikeand the loading response is not absorbed by the movement of the anklejoint and the subtalar joint and concentrates on the knee joint.Therefore, at the moment of heel strike, the knee extension moment thatallows the knee joint to straighten hinders forward rotation of the leg,so that it makes difficult for the body to move forward; in the loadingresponse, the knee flexion moment that makes the knee to be bent isexcessive, so that the forward rotation of the lower leg is not smooth;and when the quadriceps muscles are weak, the knee is abruptly bucked,and thus, stable gait is impossible, and, if severe, the patient falls.

On the other hand, in the embodiment of FIG. 4 , since the jointmovement of the hinge member is free, the rearfoot plate quickly makes aplane contact with the ground by the rotational movement of the hingejoint when the rearfoot plate contacts the ground. When the rearfootplate plane-contacts the ground at the moment of the heel strike, theload line is directed towards the ground along the longitudinal axis ofthe lower appendicular skeleton, and the ground reaction force GRFoccurs in an opposite direction thereto. In addition, the ankle jointand the subtalar joint are positioned along the longitudinal axis of theskeleton, as shown in FIG. 2 , so in this embodiment the load line andthe ground reaction force GRF at the moment of the heel strike passthrough the ankle and subtalar joints, reducing the vertical distancefrom the joint axis to the line at which the ground reaction force GRFacts (reducing the distance to the point of action of the force).Therefore, the rotating moments acting on the ankle joint and thesubtalar joint are reduced such that the movement of the joint isminimized and the joint of the hinge member compensates for the movementinstead. Since the joint of the hinge member compensates for themovement of the ankle joint and the subtalar joint even in the loadingresponse, the rotating moment caused by the ground reaction force (GRF)is not concentrated on the knee joint, so the human body smoothly movesforward.

FIG. 6 is a schematic view for explaining a second embodiment of thepresent invention and illustrates a gait assistance device.

The gait assistive device according to the second embodiment of thepresent invention includes the foot fixing part 1, the foot supportingpart 3, the rear connecting part 5, a heel part connecting member, therearfoot plate 7, and an angle maintaining part 9.

In the second embodiment of the present invention, only differences fromthe description of the first embodiment will be described, and the samecontents will be replaced by the description of the first embodiment.

The angle maintaining part 9 is for improving stability at the heelstrike in patients with a weak muscle of the coxa or knee joint or poorbalance ability. The angle maintaining part 9 causes the rearfoot plate7 to tilt to a predetermined angle when no force is applied to therearfoot plate 7. Therefore, the rearfoot plate 7 plane-contacts withthe ground G at a moment of the heel strike of a next cycle.

The angle maintaining part 9 of the second embodiment of the presentinvention may be disposed at a front side (based on the proceedingdirection of the gait) of the rearfoot plate 7.

The angle maintaining part 9 serves to restore the original state to thepitch angle at the heel strike (the angle between the ground and thefoot at the heel strike) during the heel off or toe off of the stancephase or the swing phase.

That is, the angle maintaining part 9 maintains the heel strike pitchangle when the rearfoot plate 7 is separated from the ground during thegait cycle, and thus, a patient can stably walk at a next heel strike.

The angle maintaining part 9 includes a first member 9 a coupled to thefoot supporting part 3, an elastic member 9 b coupled to the firstmember 9 a, and a second member 9 c for connecting the elastic member 9b and the rearfoot plate 7. The first member 9 a and the second member 9c may serve to support the elastic member 9 b. The elastic member 9 bmay be made of a synthetic resin material having a spring that iscompressed when a predetermined force is applied thereto and thenrestored to an initial position, or excellent restoring force.

An angle (a) (shown in FIG. 10 ) between the rearfoot plate 7 and footsupporting part 3 may be set in a range of 10 degrees to 30 degrees,preferably in a range of 20 degrees to 25 degrees. However, the anglemaintaining part 9 may be made to have a structure in which a medicalstaff may directly set it in a field according to a condition of thepatient. The angle maintaining part 9 has a function of maintaining aheel strike pitch angle during the swing phase and the second half ofthe stance phase, and also has a load adjusting function to adjust theload applied along the load line during the first half of the stancephase. In the embodiment of the present invention, when the anglemaintaining part 9 has the load adjusting function, it may be referredto as a load adjusting part in another term. When two or more anglemaintaining part 9 or the load adjusting part are installed in thetransverse direction, it may be referred to as a coronal adjusting partwhen adjusting the slope and load in the coronal plane.

FIG. 7 illustrates a gait assistance device for explaining anotherexample of the second embodiment of the present invention. Anotherexample of the gait assistance device of the second embodiment of thepresent invention is an example consisting of an assistive device forfixing the leg by the foot fixing part 1.

The foot fixing part 1 consisting of the assistive device for fixing theleg is preferably set so that the leg part and the foot part may bemaintained at an angle of about 90 degrees to each other when viewedfrom a side according to a state of a patient with central nervoussystem disease. In a case of a gait disorder caused by damage to thecentral nervous system such as a stroke, a significant rehabilitationtreatment effect is achieved by simply walking with the gait assistivedevice of the present invention, in which the leg part and the foot partare set to be maintained at about 90 degrees when viewed from the side.The foot fixing part 1 may fix the foot part and the leg part by using astrap S.

As such, when the foot fixing part 1 is applied to the rehabilitationtreatment of the patient with central nervous system disease with thefoot part and the leg part fixed, the patient may undergo gaitrehabilitation training in a state in which influence of the externalmoment, which is rotational force generated in each joint by the groundforce GRF, and the internal moment, which is rotational force generatedin each joint by the muscle contraction, is minimized. In this case, themedical staff may easily obtain, process, and standardize objective datasuch as a gait pitch or gait speed and gait stability related to thegait according to progress of the patient's condition.

In addition, the foot fixing part 1 may be formed in a hinge-coupledform to be able to adjust angles of the leg part and the foot part whenview from the side, as another example (not shown). In this case, astructure in which the medical staff or the patient may directly adjustthe angles of the leg part and the foot part may be applied.

FIG. 8 illustrates a schematic view for explaining still another exampleof the second embodiment of the present invention.

The foot fixing part 1 of the second embodiment of the present inventionmay be made of a sandal-type shoe, and may be used by a patient whosefoot and leg are fixed with a orthopedic cast. When the patient with theorthopedic cast due to fracture of the foot or leg part wears the gaitassistive device of the present invention, a natural gait is achieved,thereby further increasing the stability and treatment effect of thegait.

Particularly, the present embodiment may be used to minimize the footjoint movement of the patient suffering from diabetes, arthritis, andthe like, or to fix the foot joint movement.

When the patient wearing the gait assistive device of the secondembodiment of the present invention walks, a main operation process ofthe gait assistive device is described as follows.

FIG. 6 illustrates a state at the heel strike during the gait cycle ofthe second embodiment of the present invention.

In the description of the first embodiment of the present invention, theheel strike is realized in a state in which the rearfoot plate 7 isfree, thereby achieving the object of the present invention. In thesecond embodiment of the present invention, in a state in which theelastic member 9 b of the angle maintaining part 9 maintains the footsupporting part 3 and the rearfoot plate 7 at the constant angle (a)(shown in FIG. 10 ) by the action of a restoring force, the heel strikeis realized during the gait cycle. In this case, as described in thefirst embodiment of the present invention, the rearfoot plate 7plane-contacts the ground G. Therefore, for the reason described in thefirst embodiment of the present invention, it is possible for thepatient to walk stably without hesitation or falling.

FIG. 9 illustrates a schematic view for explaining a midstance during agait cycle of a second embodiment of the present invention.

During the midstance of the gait cycle, the elastic member 9 b of theangle maintaining part 9 is compressed to an appropriate pressure, andat the beginning of the midstance, the load line LLa is moved in frontof the center axis of the rear connecting part 5, and then, at the endof the midstance, the load line LLb is moved toward the front supportingpart 1 a.

FIG. 10 illustrates a schematic view for explaining heel off during agait cycle of a second embodiment of the present invention.

At the heel off during the gait cycle, the load line LL moves further inthe front side. In this case, the rearfoot plate 7 is separated from theground G. Then, the rearfoot plate 7 is maintained at an initial angleat which the angle maintaining part 9 is constant by the restoring forceof the elastic member 9 b. The process then proceeds to the toe off.

FIG. 11 illustrates a gait assistive device for explaining a thirdembodiment of the present invention.

In the third embodiment of the present invention, the same descriptionas that of the above-described embodiment will be replaced by thedescription of the above-described embodiment, and only differencestherebetween will be described.

In the third embodiment of the present invention, the foot supportingpart 3 is disposed long in the longitudinal direction of the foot, andthe forefoot supporting part 1 a is coupled to the front side of thefoot supporting part 3. In addition, the fixing strap S is coupled tothe foot supporting part 3. The patient or medical staff may use thestrap S to fix the gait assistive device to the foot fixing part 1 ofthe foot or shoe. The third embodiment of the present invention may begenerally and easily applied to patients with different foot sizes orvarious physical conditions.

FIG. 12 illustrates a gait assistive device for explaining a fourthembodiment of the present invention.

In the fourth embodiment of the present invention, the same descriptionas that of the above-described embodiment will be replaced by thedescription of the above-described embodiment, and only differencestherebetween will be described.

In the fourth embodiment of the present invention, the angle maintainingpart 9 is made of a tension spring, and is installed at a rear side ofthe rear connecting part 5. In the fourth embodiment of the presentinvention, force acts in a direction in which the angle maintaining part9 made of the tension spring always pulls the foot supporting part 3 andthe rearfoot plate 7. Therefore, the fourth embodiment of the presentinvention may easily configure the second embodiment of the presentinvention, and may include various embodiments.

FIG. 13 illustrates a gait assistive device for explaining a fifthembodiment of the present invention.

In the fifth embodiment of the present invention, the same descriptionas that of the above-described embodiment will be replaced by thedescription of the above-described embodiment, and only differencestherebetween will be described.

In the fifth embodiment of the present invention, the angle maintainingpart 9 is made of a torsion spring, and is installed at the rearconnecting part 5. In the fifth embodiment of the present invention,force acts in a direction in which the angle maintaining part 9 made ofthe torsion spring always pushes the foot supporting part 3 and therearfoot plate 7. Therefore, according to the fifth embodiment of thepresent invention, component parts thereof are gathered and disposed inone place, thereby simplifying appearance thereof and reducingmanufacturing costs thereof. The fifth embodiment of the presentinvention may also be configured, and include various embodiments.

FIG. 14 illustrates a schematic view of an angle maintaining part 9 thatmay set an angle of a rearfoot plate 7 of a gait assistive device forexplaining a sixth embodiment of the present invention.

In the sixth embodiment of the present invention, the same descriptionas that of the above-described embodiment will be replaced by thedescription of the above-described embodiment, and only differencestherebetween will be described.

The sixth embodiment of the present invention has a structure in whichthe medical staff may properly adjust the angle maintaining section 9according to the condition of the patient. That is, the anglemaintaining part 9 of the sixth embodiment of the present invention mayinclude an air chamber 11, a return spring 13, a flow adjusting valve15, and a check valve 17.

The air chamber 11, which is a space into which outside air may beintroduced, may be formed to have a bellows shape. The air chamber 11may be disposed between the foot supporting part 3 and the rearfootplate 7. The air chamber 11 may be disposed between the foot supportingpart 3 and the rearfoot plate 7, thus both ends thereof may be fixed.The return spring 13 may be disposed outside the air chamber 11. The airchamber 11 may also be disposed between the foot supporting part 3 andthe rearfoot plate 7. The flow control valve 15 may be installed in aconduit 15 a connected to the air chamber 11, or may be directlyinstalled in the air chamber 11. The flow adjusting valve may beadjusted to control the speed of air discharged from the air chamber 11by manually or automatically adjusting a size of a discharge passage.

Since the medical staff adjusts an amount of the air discharged to theair chamber 11 through the flow adjusting valve 15 according to thecondition of the patient, the flow adjusting valve 15 may set the angleof the rearfoot plate 7 at an optimum value. The check valve 17 preventsoutside air from being discharged to the outside while allowing theoutside air to flow into the air chamber 11. The check valve 17 may beinstalled in a conduit 17 a connected to the air chamber 11, or may bedirectly installed in the air chamber 11.

Although the description of the embodiment of the present invention usesa pneumatic mechanism as an instance to explain the air chamber 11, thechamber is not limited to using air as a medium and it can utilize afluid consisted of both air and liquid.

Hereinafter, an operational process of the sixth embodiment of thepresent invention will be described.

The air chamber 11 is compressed while the patient walks. In this case,the medical staff adjusts a degree to which the air chamber 11 iscompressed. Thus, when some of the air of the air chamber 11 isdischarged to the outside through the flow adjusting valve 15, the airchamber 11 is not compressed any more and is maintained in the adjustedstate. The air chamber 11 is restored to an initial state by the returnspring 13 at the heel off during the gait cycle. In this case, while theair chamber 11 is restored to an initial position, outside air isintroduced into the air chamber 11 through the check valve 17 by anegative pressure of the air chamber 11. Therefore, even though thepatient repeatedly walks, the medical staff may always set aninclination of the rearfoot plate 7 at a desired value set by themedical staff.

The sixth embodiment of the present invention may be adapted to gaitassistive devices customized to patients of various conditions.

In the first to sixth embodiments of the present invention, the rearfootplate 7 of the gait assistive device may be set at an inclination withrespect to a sagittal plane corresponding to the longitudinal direction.

FIG. 15 illustrates a rear connecting part 5 of a gait assistance devicefor explaining a seventh embodiment of the present invention, FIG. 16illustrates a side view of a state in which the rear connecting part ofFIG. 15 is assembled, and FIG. 17 illustrates a rear side of a state inwhich the rear connecting part of FIG. 15 is assembled.

In the seventh embodiment of the present invention, the same descriptionas that of the above-described embodiment will be replaced by thedescription of the above-described embodiment, and only differencestherebetween will be described.

The seventh embodiment of the present invention is an example having astructure in which the inclination at the sagittal plane (the pitch) ofthe rear connecting part 5 and the inclination at the coronal plane (theroll) thereof may be adjusted at the same time.

The rear connecting part 5 of the seventh embodiment of the presentinvention may be formed of an ellipsoid joint. That is, the rearfootplate 7 may be integrally molded with or coupled to a convex portion 19a of an ellipsoid, and the foot supporting part 3 may be integrallymolded with or coupled to a concave portion 19 b of the ellipsoidcorresponding to the convex portion 19 a of the ellipsoid. It may bemade of a structure that is molded or bonded. Of course, the rearfootplate 7 may be integrally molded with or coupled to the concave portionof the ellipsoid, and the foot supporting part 3 may be integrallymolded with or coupled to the convex portion of the ellipsoid.

Referring to FIG. 15 , the convex portion 19 a of the ellipsoid formedin the rearfoot plate 7 has a width w1 in the width direction of thefoot and a width w2 in the length direction of the foot. The width w1 inthe width direction is formed larger than the width w2 in the lengthdirection, and an upper surface thereof forms an ellipsoid. Of course,the ellipsoid concave portion 19 b formed in the foot supporting part 3is formed in a shape corresponding to the ellipsoid convex portions 19 aformed in the rearfoot plate 7 and is coupled thereto. The seventhembodiment of this invention has two degrees of freedom in which therearfoot plate 7 may move in the sagittal plane and the coronal plane.Since such a structure of the seventh embodiment of the presentinvention allows the rearfoot plate 7 to move not only in the sagittalplane but also in the coronal plane, it can sufficiently help with thepatient's stable gait.

In another example of the seventh embodiment of the present invention, asaddle joint having two degrees of freedom may be applied to the rearconnecting part 5.

FIG. 18 illustrates a rear connecting part 5 of a gait assistance devicefor explaining an eighth embodiment of the present invention, and FIG.19 illustrates an exploded perspective view of a main part of the rearconnecting part 5 of the gait assistance device shown in FIG. 18 .

In the eighth embodiment of the present invention, the same descriptionas that of the above-described embodiment will be replaced by thedescription of the above-described embodiment, and only differencestherebetween will be described. The rear connecting part 5 of the eighthembodiment of the present invention has a structure having two degreesof freedom as in the seventh embodiment. The rear connecting part 5 ofthe eighth embodiment of the present invention includes a first member21 coupled to the rearfoot plate 7, a second member 23 coupled to thefirst member 21 to move in the sagittal plane, and a third member 25coupled to the second member 23 to move in the coronal plane and to becoupled to the foot supporting part 3.

The first member 21 is formed with a concave curved portion 21 a toallow the second member 23 to move to the sagittal plane. In addition,the second member 23 is formed with a convex curved portion 23 acorresponding to the concave curved portion 21 a. Further, anotherconcave curved portion 23 b is formed on an upper surface of the secondmember 23. The concave curved portion 23 b formed on the second member23 is preferably formed to be perpendicular to the concave curvedportion 21 a formed on the first member 21. In addition, the thirdmember 25 is formed with another convex curved portion corresponding tothe concave curved portion 23 b of the second member 23.

The rear connecting part 5 of the eighth embodiment of the presentinvention configured as described above has two degrees of freedom as inthe rear connecting part 5 described in the seventh embodiment, and Itmay move more securely the rearfoot plate 7 to the sagittal and coronalplanes while sufficiently supporting the patient's weight.

Both the seventh and eighth embodiments correspond to joints that havetwo degrees of freedom, which are capable of rotational movement in thesagittal plane and in the coronal plane, and in another embodiment,universal joints may be applied.

FIG. 20 illustrates a rear portion of a foot in a coronal plane, in astate in which a load line passes through an ankle joint and a subtalarjoint in the seventh and eighth embodiments of the present invention.

Since a joint of the rear connecting part may be rotated in the coronalplane, the load line is directed to the ground along the longitudinalaxis of the lower appendicular skeleton even in the coronal plane as inthe first embodiment of FIG. 4 . Therefore, the rotating moments actingon the ankle joint and the subtalar joint are reduced even in thecoronal plane, so that the movement of the joint is minimized, and thejoint of the rear connecting part compensates for the pronationmovements of the subtalar joint instead. Therefore, the patient mayperform a more stable gait.

FIG. 21 illustrates a schematic view for explaining a conventionalexample corresponding to FIG. 20 .

FIG. 21 illustrates a point time of the heel strike in the coronalplane, during the gait cycle in a state of wearing a general shoe. Inthe gait in the state of wearing the general shoe, a point contact ismade between the ground G and the outside of the shoe at a moment of theheel strike.

As in FIG. 5 showing the sagittal plane, the load line LL and the groundreaction force GRF are generated at the contact point. The rotationalmoment cause by the ground reaction force (GRF) rotates the foot locatedbelow the subtalar joint B in a direction of an arrow in the coronalplane (see FIG. 21 ).

In the normal case, the rotating moment causes pronation movement of thesubtalar joint to absorb and disperse an impact from the ground, butwhen normal movements of the joints of the ankle and the foot areimpossible, the gait stability is reduced.

FIG. 22 illustrates a bottom view of a gait assistive device forexplaining a ninth embodiment of the present invention.

The ninth embodiment of the present invention has a structure in whichtwo angle maintaining parts 9 are disposed side by side in the rearfootplate 7 in the width direction of the rearfoot plate 7 so that therearfoot plate 7 corresponds to all movements of the sagittal plane andthe coronal plane. In this case, the angle maintaining part 9 describedin the above-described embodiment may be used. In the ninth embodimentof the present invention, the inclination of the sagittal plane and theinclination of the coronal plane of the rearfoot plate 7 may besimultaneously set. According to the structure of the ninth embodimentof the present invention, the gait of the patient may be more stable.

FIG. 23 illustrates a schematic view of a rear connecting part 5 of agait assistance device for explaining a tenth embodiment of the presentinvention.

In the tenth embodiment of the present invention, the same descriptionas that of the above-described embodiment will be replaced by thedescription of the above-described embodiment, and only differencestherebetween will be described.

The tenth embodiment of the present invention shows an example in whichthe rear connecting part 5 has a ball and socket joint structure. In thetenth embodiment of the present invention, an accommodating part 31 iscoupled to the rearfoot plate 7, and a ball part 33 that is in contactwith the accommodating part 31 is coupled to the foot supporting part 3.The accommodating part 31 and the ball part 33 are preferably formed tohave a hemispherical shape. According to this structure, due to thespherical shape, it is possible to lower the heights of the footsupporting part 3 and the rearfoot plate 7, and at the same time, toensure the stability of operation. The tenth embodiment of the presentinvention shows the features that have multiple degrees of freedom andin which the ball joint (or ball-socket joint) may be applied to thepresent invention.

FIG. 24 illustrates a schematic view of a gait assistance device forexplaining an eleventh embodiment of the present invention.

The rear connecting part 5 of the eleventh embodiment of the presentinvention may be made of a universal joint having two degrees offreedom. In addition, the foot supporting part 3 is made long in thelongitudinal direction of the foot. Further, a front supporting part 41hinged to the front side of the foot supporting part 3 may be provided.The eleventh embodiment of the present invention also shows that thepresent invention may be variously configured.

FIG. 25 illustrates a schematic view of a gait assistance device forexplaining a twelfth embodiment of the present invention.

In the twelfth embodiment of the present invention, the same descriptionas that of the above-described embodiment will be replaced by thedescription of the above-described embodiment, and only differencestherebetween will be described.

In the gait assistive device of the twelfth embodiment of the presentinvention, the foot fixing part 1 consists of an assistive device forfixing the leg and the foot.

The foot fixing part 1 consisting of the assistive device for fixing theleg is preferably set so that the leg part and the foot part may bemaintained at an angle of about 90 degrees to each other, in a sectionalview, according to the state of the patient with the central nervoussystem disease. In the case of the gait disorder caused by the damage tothe central nervous system such as a stroke, a significantrehabilitation treatment effect is achieved by simply walking with thegait assistive device of the present invention, which is set at a statein which the leg and the foot are maintained at about 90 degrees whenviewed from the side. The foot fixing part 1 may fix the foot supportingpart 3 with a fastening member such as a screw, and it may be integrallyformed with the foot supporting part 3.

The foot fixing part 1 fixing the leg part and the foot part may fix thefoot part and the leg part by using the strap S.

In addition, the foot supporting part 3 may be coupled to a forefootplate 51. The forefoot plate 51 may have the same structure as that ofthe thirteenth embodiment, so a description thereof will be replaced bythat of the thirteenth embodiment.

FIG. 26 illustrates a schematic view of a gait assistance device forexplaining a thirteenth embodiment of the present invention, and FIG. 27illustrates an exploded perspective view of a main part of FIG. 26 .

The gait assistive device of the thirteenth embodiment of the presentinvention includes the foot supporting part 3, the rear connecting part5, the rearfoot plate 7, a front connecting part 6, the forefoot plate51, a plate connecting part 81, and a coronal adjusting part 91.

In the thirteenth embodiment of the present invention, the samedescription as that of the above-described embodiment will be replacedby the description of the above-described embodiment, and onlydifferences therebetween will be described.

The foot supporting part 3 of the thirteenth embodiment of the presentinvention will be described with reference to FIG. 27 to FIG. 29 . Thefoot supporting part 3 of the thirteenth embodiment of the presentinvention may include a base 301, a rear moving member 303, a rearadjusting member 305, a front moving member 309, a front adjustingmember 311, and a cover 313.

The base 301 is formed long in the length direction of the foot. Thebase 301 is formed with a slide hole 301 a at a rear side thereof. Guidegrooves 301 b are formed in a longitudinal direction of the base 301 atboth sides of the slide hole 301 a.

The rear moving member 303 is inserted into the slide hole 301 a, and isprovided with a guide protrusion 303 a corresponding to the guide groove301 b. Accordingly, the rear moving member 303 may move along the guidegroove 301 b in the longitudinal direction of the base 301. On the otherhand, a central portion of the base 301 is provided with a hole h in thelongitudinal direction in the center portion. The rear moving member 303is provided with a screw hole 303 c in a longitudinal direction thereof.The rear adjusting member 305 may be made of a bolt member having athread formed on an outer circumferential surface thereof. The rearadjusting member 305 may be coupled to the hole h of the base 301 andthe screw hole 303 c of the rear moving member 303 to move the rearmoving member 303 in the longitudinal direction of the base 301 whilefixing the rear moving member 303 to the base 301

On the other hand, the rear moving member 303 is coupled to one side ofthe rear connecting part 5. Therefore, the rear moving member 303 maymove a central axis of the rear connecting part 5 while moving in thelongitudinal direction of the base 301. According to this structure, itis possible to move the axis of the rear connecting part 5 to the rearside of the load line LL in consideration of the load line LL accordingto the condition of the patient.

In addition, the base 301 is provided with another slide hole 301 c atthe front side thereof. Guide grooves 301 d are formed in thelongitudinal direction of the base 301 at both sides of the slide hole301 c.

The front moving member 309 is inserted into the slide hole 301 c, andis provided with a guide protrusion 309 a corresponding to a guidegroove 301 d. Accordingly, the front moving member 309 may move in thelongitudinal direction of the base 301 along the guide groove 301 d.Meanwhile, a central portion of the base 301 is provided with anotherhole h in the longitudinal direction thereof. The front moving member309 is provided with a screw hole 309 c in the longitudinal direction.The front adjusting member 311 may be made of a bolt member formed witha thread on an outer circumferential surface thereof. The frontadjusting member 311 may be coupled to the hole h of the base 301 andthe screw hole 309 c of the front moving member 309 to move the frontmoving member 309 in the longitudinal direction while fixing the frontmoving member 309 to the base 301.

On the other hand, the front moving member 309 is coupled to one side ofthe front connecting part 6. Therefore, the front moving member 309 maymove a central axis of the front connecting part 6 while moving in thelongitudinal direction of the base 301. According to this structure, itis possible to move the axis of the front connecting part 6 to the rearside of the load line LL in consideration of the load line LL accordingto the condition of the patient.

Meanwhile, the cover 313 may be coupled to the base 301 to fix the rearmoving member 303 and the front moving member 309 to be not separatedtoward the outside.

Referring to FIG. 29 , when it is necessary to move an axis C of therear connecting part 5 in the longitudinal direction, the medical staffmoves the rear moving member 303 in consideration of the condition ofthe patient and the load line LL. That is, when the rear adjustingmember 305 is rotated, the rear adjusting member 305 rotates in place.Then, the rear adjusting member 305 is screw-coupled to the rear movingmember 303, so that the rear moving member 303 moves in the longitudinaldirection of the base 301 along the guide groove 301 b of the base 301and the guide protrusion 303 a of the rear moving member 303.

Since the front moving member 309 may also move in the same manner as inthe rear moving member 303, a description of a moving process of thefront moving member 309 is replaced with the above description.

In the thirteenth embodiment of the present invention, the rearconnecting part 5 and the front connecting part 6 may be made of auniversal joint. However, the rear connecting part 5 and the frontconnecting part 6 may include the examples described in theabove-described embodiment.

The rear connecting part 5 and the front connecting part 6 may bepivotally coupled to the rearfoot plate 7 and the forefoot plate 51 bypivot coupling parts 101 and 103, respectively. Thus, the rearfoot plate7 may have three degrees of freedom that may be rotated in the sagittalplane, the coronal plane, and a horizontal plane. In addition, theforefoot plate 51 may also be moved with three degrees of freedom.

FIG. 30 illustrates a schematic view of a plate connecting part of thethirteenth embodiment of the present invention.

As drawings for explaining a plate connecting part 81 of the thirteenthembodiment of the present invention, FIG. 30 (a) shows a single type ofthe plate connecting part 81, and FIG. 30 (b) shows a double type of theplate connecting part 81.

The plate connecting part 81 of the thirteenth embodiment of the presentinvention has a pin-slot joint structure. That is, referring to FIG. 30(a), a first link 351 is coupled to the rearfoot plate 7, and a secondlink 353 is coupled to the forefoot plate 51.

The first link 351 and the second link 353 extend in the longitudinaldirection of the foot. The first link 351 is provided with a long hole351 a in the longitudinal direction of the foot. In addition, the secondlink 353 is coupled to a shaft part 353 a fitted in the long hole 351 aof the first link 351 in the width direction of the foot. Thus, therearfoot plate 7 and the forefoot plate 51 are linearly translated androtated in the sagittal plane in a linked state. FIG. 30 (b) illustratesan example in which the first link 351 and the second link 353 aredisposed in pairs in the width direction of the foot. When therespective links are configured in pairs as described above, it ispossible to prevent a sliding motion from being disturbed due totwisting of the rearfoot plate 7 and the forefoot plate 51. The plateconnecting part 81 may be used as a single type or a double typeaccording to design needs.

FIG. 31 illustrates an operation example of a coronal adjusting part 91of the thirteenth embodiment of the present invention.

The coronal adjusting part 91 of the thirteenth embodiment of thepresent invention may have a structure using liquid or hydraulicpressure. The coronal adjusting part 91 may be disposed in pairs in thewidth direction of the foot. The coronal adjusting part 91 disposed at aleft side with reference to FIG. 31 includes a hydraulic chamber 441, areservoir tank 443, a discharge conduit 441 a, a return conduit 443 a, ahydraulic control valve 445, and a check valve 447. The hydraulicchamber 441 may be a bellows type of chamber in which oil is filled, anda height thereof is variable. The hydraulic chamber 441 may dischargeoil to the reservoir tank 443 through the discharge conduit 441 a. Thehydraulic control valve 445 is installed in the discharge conduit 441 a.The hydraulic control valve 445 may be adjusted so that the medicalstaff may discharge the oil contained in the hydraulic chamber 441 at adesired speed and amount. The hydraulic control valve 445 may bemanually operated. The return conduit 443 a may be connected between thereservoir tank 443 and the hydraulic chamber 441, and thus the oil inthe reservoir tank 443 may be returned to the hydraulic chamber 441. Thecheck valve 447 is installed in the return conduit 443 a so that the oilcontained in the hydraulic chamber 441 may not be discharged to thereturn conduit 443 a and the oil of the reservoir tank 443 may flow intothe hydraulic chamber 441.

The coronal adjusting part 91 disposed at a right side with reference toFIG. 31 includes a hydraulic chamber 451, a reservoir tank 443, adischarge conduit 451 a, a return conduit 453 a, a hydraulic controlvalve 455, and a check valve 457. The hydraulic chamber 451 may be abellows type of chamber in which oil is contained, and a height thereofis variable. In addition, the hydraulic chamber 451 may discharge oil tothe reservoir tank 443 through the discharge conduit 451 a. Thehydraulic control valve 455 is installed in the discharge conduit 451 a.The hydraulic control valve 455 may be adjusted so that the medicalstaff may discharge the oil contained in the hydraulic chamber 451 at adesired speed and amount. The hydraulic control valve 455 can bemanually operated. The return conduit 453 a may be connected between thereservoir tank 443 and the hydraulic chamber 451, and thus the oil inthe reservoir tank 443 may be returned to the hydraulic chamber 451. Thecheck valve 457 is installed in the return conduit 453 a so that the oilcontained in the hydraulic chamber 451 may not be discharged to thereturn conduit 453 a and the oil of the reservoir tank 443 may flow intothe hydraulic chamber 451.

The coronal adjusting part 91 configured as described above adjusts thehydraulic control valves 445 and 455 according to the gait state of thepatient at the heel strike during the gait cycle. That is, the medicalstaff controls the discharge amount of the hydraulic chambers 441 and451 by adjusting the hydraulic control valves 445 and 455 at the heelstrike during the gait cycle of the patient. The medical staff adjuststhe hydraulic control valves 445 and 455 to lower heights of thehydraulic chambers 441 and 451 optimized for an individual patient (seeFIG. 36 ). That is, as illustrated in FIG. 36 , heights h1 and h2 of theleft and right hydraulic chambers 441 and 451 become different to beoptimized for the individual patients.

FIG. 32 illustrates a schematic view for explaining a relative positionof a load line LL with respect to an axis of a rear connecting part at aheel strike during a gait cycle of the thirteenth embodiment of thepresent invention.

In the gait assistive device of the thirteenth embodiment of the presentinvention, a position at which the rearfoot plate 7 plane-contacts theground G at the heel strike during the gait cycle is the same as thoseof the first and second embodiments described above. In the gaitassistive device according to the thirteenth embodiment of the presentinvention, the joint axis of the rear connecting part 5 at the heelstrike during the gait cycle may be set at the line of the load line LLor at the rear side of the load line LL at the heel strike during thegait cycle based on the proceeding direction of the gait. In the gaitassistive device of the thirteenth embodiment of the present invention,the rearfoot plate 7 and the forefoot plate 51 may be adjusted in thesagittal plane by a coupled movement by the plate connecting part 81,and at the same time, they may be adjusted in the coronal plane by thecoronal adjusting part 91.

The gait assistive device of the thirteenth embodiment of the presentinvention may be applied to the patient by simultaneously optimizing theadjustment of the coronal plane and the sagittal plane at the heelstrike of the patient's gait cycle.

In addition, in the thirteenth embodiment of the present invention, thecoronal adjusting part 91 is installed in the forefoot plate 51 having asufficient space, which is advantageous in terms of design andmanufacture.

FIG. 33 illustrates a schematic view for explaining a position at whichthe load line LL is moved in the process of the midstance during thegait cycle of the thirteenth embodiment of the present invention.

At the midstance during the gait cycle, the load line LLa at an initialtime point of the midstance moves to the load line LLb at an end timepoint of the midstance.

A movement process of the load line LL is the same as that of theabove-described embodiment.

FIG. 34 illustrates a schematic view for explaining a position of theload line LL in the process of the heel off during the gait cycle of thethirteenth embodiment of the present invention.

At the heel off during the gait cycle, the rearfoot plate 7 is separatedfrom the ground G while the load line LL moves forward.

In addition, the rearfoot plate 7 is moved in interlocking with theforefoot plate 51 by the coronal adjusting part 9 and the plateconnecting part 81 such that the angle therebetween is maintained andthe movement in the sagittal plane and the coronal plane may beoptimized.

FIG. 35 illustrates a schematic view for explaining a position of theload line LL in the process of the toe off during the gait cycle of thethirteenth embodiment of the present invention.

At the toe off during the gait cycle, the load line LL moves furtherforward. After that, the process of the swing phase is performed. In anormal gait, the load line LL moves according to the progression forcegenerated by swing of the contralateral leg and the forward movement ofthe human body in the second half of the stance phase which is from themidstance to the toe off. In this case, the movement of the joints ofankle and foot causes the foot to act like a rocker (a bottom of arocking chair) to enable energy efficient and a smooth gait.

As shown in the thirteenth embodiment, when the joint of the frontconnecting part is installed between the load line formed at the heeloff and the load line formed at the toe off, it may perform a functionsimilar to a rocker, even when the joints of ankle and foot arepathological or are limited in their movement.

FIG. 37 illustrates a schematic view for explaining a fourteenthembodiment of the present invention, and FIG. 38 illustrates across-sectional view taken along line A-A of FIG. 37 .

The fourteenth embodiment of the present invention provides anotherexample of the coronal adjusting part 91. The coronal adjusting part 91of the fourteenth embodiment of the present invention includes a firstmember 501, a second member 503, and an elastic member 505. The firstmember 501 is provided with a space therein, and is coupled to theforefoot plate 51. The first member 501 is provided with a thread formedon an outer circumferential surface thereof. The first member 501 mayhave a cylindrical shape. The second member 503 has a cylindrical shape,and a screw groove is formed on an inner circumferential surfacethereof. Therefore, the second member 503 may relatively move to thefirst member 501 while being screw-coupled to the first member 501 to berotated. That is, the second member 503 may adjust a distance betweenthe rearfoot plate 7 and an upper surface of the second member 503 whilebeing rotated and moved to the first member 501. It is also possible forthe upper surface of the second member 503 to serve as a stopper withrespect to the foot supporting part 3. The elastic member 505 may bemade of rubber, a synthetic resin, or the like having excellentrestoring force.

At the swing phase after the toe off during the gait cycle, it may bequickly restored to the position set by the medical staff to beoptimized for the patient. The fourteenth embodiment of the presentinvention shows that the coronal adjusting part 91 that may be set bythe medical staff may be variously configured.

FIG. 39 illustrates a schematic view for explaining a fifteenthembodiment of the present invention, and FIG. 40 illustrates across-sectional view taken along line B-B of FIG. 39 .

The fifteenth embodiment of the present invention shows another exampleof the coronal adjusting part 91. Compared with the aforementionedfourteenth embodiment, a feature of the fifteenth embodiment that isdifferent from the aforementioned fourteenth embodiment will be mainlydescribed, and a description of the same feature as that of theaforementioned fourteenth embodiment follows that of the aforementionedfourteenth embodiment. In the fifteenth embodiment of the presentinvention, the elastic member includes a compression coil spring 507. Astructure in which the second member 503 relatively rotates and moves tothe first member 501 is the same as that of the fourteenth embodimentdescribed above.

FIG. 41 illustrates a cross-sectional view for explaining a sixteenthembodiment of the present invention.

Compared with that of the sixteenth embodiment, a feature of the coronaladjusting part 91 of the sixteenth embodiment that is different fromthat of the aforementioned sixteenth embodiment will be mainlydescribed, and a description of the same feature as that of theaforementioned sixteenth embodiment follows that of the aforementionedfifteenth embodiment.

The coronal adjusting part 91 of the sixteenth embodiment of the presentinvention further includes a guide 509 protruding in the direction ofthe forefoot plate 51 from the foot supporting part 3, and an angleadjusting member 511. The guide 509 may be welded or screw-coupled tothe foot supporting part 3, and is threaded on an outer circumferentialsurface thereof. The angle adjusting member 511 is provided with a screwgroove on an inner circumferential surface to be screw-coupled to theguide 509. Therefore, a distance between the foot supporting part 3 andthe forefoot plate 51 may be adjusted by rotation of the angle adjustingmember 511, and since the forefoot plate and the forefoot plate movewhile interlocking with each other, when the distance is previously set,an angle between the ground and foot can be adjusted at the heel strike.Therefore, stability may be improved at the heel strike.

FIG. 42 illustrates a schematic view for explaining a seventeenthembodiment of the present invention.

The seventeenth embodiment of the present invention shows a gaitassistive device which may be worn on a general shoe. That is, in thegait assistive device of the seventeenth embodiment of the presentinvention, the foot supporting part 3 may be separately formed from thefoot fixing part 1. In addition, the foot supporting part 3 is providedwith the strap S, so that it may be fixed to the foot fixing part 1 suchas the shoe and used. Further, the gait assistive device of theseventeenth embodiment of the present invention may include the footsupporting part 3, the rear connecting part 5, the rearfoot plate 7, thefront connecting part 6, the forefoot plate 51, the plate connectingplate 81, and the coronal adjusting part 91. That is, the examplesdescribed above may be applied to the gait assistive device according tothe seventeenth embodiment of the present, as it is.

FIG. 43 illustrates a schematic view for explaining an eighteenthembodiment of the present invention. The eighteenth embodiment of thepresent invention is a modification of the sixth embodiment (FIG. 14 )described above.

Compared with the sixth embodiment, a feature of the eighteenthembodiment that is different from the sixth embodiment will bedescribed. The eighteenth embodiment of the present invention furtherincludes a first member 20 coupled to the rearfoot plate 6 and a secondmember 22 screw-coupled to the first member. The first member 20 has acylindrical shape, and is provided with a space in which the air chamber11 may be accommodated. The first member is threaded on an outercircumferential surface thereof. The second member 22 has a nut shape ofwhich an inner circumferential surface is formed with a screw groove.Therefore, the second member 22 is screw-coupled to the first member 20.The second member 22 is provided with a groove portion 22 a into whichthe return spring 13 may be fitted in a surface facing the footsupporting part 3 along a circumferential direction. In addition, oneend of the return spring 13 is fitted into the groove portion 22 a ofthe second member 22, and the other end thereof is in contact with thefoot supporting part 3.

Therefore, the return spring 13 elastically supports between the footsupporting part 3 and the second member 22. The eighteenth embodiment ofthe present invention, as in the angle adjusting member shown in thesixteenth embodiment of FIG. 41 , causes plane-contact with the groundat the heel strike, thereby increasing stability at the heel strike.

By adjusting the tension of the return spring 13, the medical staff mayuse it in an optimized state according to the state of the patient orgait. The gait assistive device of the embodiments of the presentinvention may be used as a bottom structure of a walking robot or adevice for walking.

While this invention has been described in connection with what ispresently considered to be practical embodiments, it is to be understoodthat the invention is not limited to the disclosed embodiments, but, onthe contrary, is intended to cover various modifications and equivalentarrangements included within the spirit and scope of the appendedclaims.

DESCRIPTION OF SYMBOLS

-   -   1. foot fixing part    -   1 a. forefoot supporting part    -   3. foot supporting part    -   5. rear connecting part    -   6. front connecting part    -   7. rearfoot plate    -   9. angle maintaining part    -   11. air chamber    -   13. return spring    -   15. flow adjusting value    -   17. check value    -   51. forefoot plate    -   81. plate connecting part    -   91. coronal adjusting part

What is claimed is:
 1. A gait assistive device comprising: a footsupporting part; a rear connecting part coupled to a heel portion of thefoot supporting part; and a rearfoot plate coupled to the rearconnecting part, wherein the rear connecting part includes a joint, andthe joint allows movement of the rearfoot plate to make plane contactwith a ground at a moment of a heel strike during a gait cycle and tomove in coronal and sagittal planes, wherein an angle maintaining partis disposed between the foot supporting part and the rearfoot plate, theangle maintaining part causes the rearfoot plate to tilt to apredetermined angle at a second half of a stance phase or a swing phase,the rearfoot plate makes a plane contact with the ground at a moment ofthe heel strike.
 2. The gait assistive device of claim 1, wherein thefoot supporting part is coupled to a front supporting part at a frontside of the foot.
 3. The gait assistive device of claim 1, wherein thefoot supporting part is coupled to a front connecting part at a frontside of the foot supporting part, and a forefoot plate coupled to thefront connecting part.
 4. The gait assistive device of claim 1, whereina coronal adjusting part that transversely adjusts the rearfoot plate isinstalled between the rearfoot plate and the foot supporting part. 5.The gait assistive device of claim 3, wherein a coronal adjusting partthat transversely adjusts the forefoot plate is disposed between theforefoot plate and the foot supporting part.
 6. The gait assistivedevice of claim 1, wherein a load adjusting part that adjusts a loadapplied at a first half of a stance phase is disposed between the footsupporting part and the rearfoot plate.
 7. The gait assistive device ofclaim 4, wherein the coronal adjusting part is made of at least one ofan elastic member, a torsion spring, and a chamber provided with a spaceaccommodating a fluid, and the chamber is connected to a flow adjustingvalve that adjusts an amount of the fluid of the chamber.
 8. The gaitassistive device of claim 5, wherein the coronal adjusting part is madeof at least one of an elastic member, a torsion spring, or a chamberprovided with a space accommodating a fluid, and the chamber isconnected to a flow adjusting valve that adjusts an amount of the fluidof the chamber.
 9. A walking robot comprising the gait assistive deviceaccording to claim 1.